Gauge Malfunctioning

[Hanaldo]

Hey all,

This isn't audio or security, but there is no general electrical section so I thought this is probably where all the electrical gurus are hanging out

Basically a few months ago I cleaned my engine bay after an oil spill, and my Shadow Pro oil temperature gauge has an inline plug to connect the temp sensor to the rest of the harness. Well this connection got water/degreaser inside of it (not a lot, maybe a drop), and the gauge no longer works. It turns on and everything, but it reads like the oil is warming up at an alarming rate, and will then usually sit above 110 degrees occasionally jumping around to 150 then straight down to 80, back up again, etc.

It has happened before, but I unplugged the connection and let it dry overnight and it was fine the next day. Tried it again this time, even used a small piece of paper towel to absorb any moisture around the pins. Also tried using some electrical cleaner. Still doesn't work. So my question is, is there anything I can do or is it fried? Is it more likely to be the sensor that is busted or the gauge itself?

Thanks for any help,

Martin.

[Carbon 34]

could be both without testing power and grounds and if its getting signal know way to tell buy a digital voltage meter and test it , or take to to get tested.

degreasing a engine on a nissan is a death sentence without care, the connections fail really easy in the heat here and crust from salty air, degreaser from kerosene is bad news. and spray tins stain your block anyway, use the natural stuff works better anyhow

never on running engine, super hot engine

use silicone spray on all electronics connections at the least before and after a big wash up , and tape up or cover things like the CAS, etc when hosing off . dont spray inside the alternator with anything not made for it, and never while running , to risky to fry it

never wash it super hot or let water into the plug valley if you can help it , death to coils and ground issues.

gauges work by seeing the restance to ground or 0V in most cases. so to little or to much voltage will give you varied readings, a bad sender can do that as well, oil senders can get plugged with crap inside.

just 1 drop of water???? , try 1 drop on a pc mother board, watch the smoke its pretty same on anything electronic curcuit based

[Hanaldo]

Yeh don't get me wrong, I wasn't spraying a hose in the engine bay. Was using a cloth with degreaser on it, but unfortunately there was oil near the gauge connection and I accidentally got a little trigger happy. The engine wasn't hot and I didn't start it until the next day to make sure everything was dry.

Can I test with a multimeter? What am I testing for, resistance/voltage?

Thanks mate.

Edited February 1, 2012 by Hanaldo

[Carbon 34]

depends on the gauge, since I dont have the instructions and most are made in china, is that from just jap ? do you have the install instruction, that would be helpful to see the wires connection point,

you need 12v at the gauge rear , most likely a red wire with fuse, check the fuse as well, or if the power is from something else to the gauge check that fuse is ti blown ? ie cig lighter fuse

you need to make sure the ground, prob black or maybe green as a ground colour , some multi meters have a ohm beep test noise, use that put on ground wire and bare metal on the car , pin switch screw heads, or the ignition barrel sits at ground , you should hear a beep if the ground is good, turn on the parking lights does the beep stop, bad ground to wrong wire

then you have the sensor wire, is that just one wire ? prob is, if you hold the ohm resitance part of the multimeter on that wire with the other to ground you can check the ohm load while cold, jot it down then try it after a few min of runnning , jot it down, runt he engine till warm, jot it down, if the numbers go either up or down in order that should be working

like 10 ohms cold, 30ohms warm, 50ohms hot or vise versa, then i would say the sensor is working and sending the right signal but you have another issues with above items

you might have another wire, for lights, dimmer

once you take the ohm load at engine side, also check the gauge side same wire , is the ohm load close to the same engine side on each test if no ohm load , then you have a broken wire or bad connection between the gauge and engine.

how is it plugged in exactly, is it piggybacked on to the harness factory wire or stand alone sensor sender ? it sounds like it just bridges a gap between the factory sensors and your dash wires is that right ?

it should be fairly easy to suss , think 3 maybe 4 wires tops, you need power, ground and signal/sensor wire , and some have a illumination wire but doubt it on the newer ones.

I noticed you said , GT with GTT engine, which is a different harness isnt it ? pretty sure without pulling out the diagram it is.

just curious does everthing else in the car still work, no other non working items, blown fuses ?

worse case is pull the gauge under warranty return it, or if no warranty , power it from a few wires to the battery to see if it powers up minus the harness ? do you get anything now? lights at all ?

Edited February 1, 2012 by Carbon 34

[Hanaldo]

Yeh its not busted completely, it still works. It just gives crazy readings as I said in my first post. So is that more likely to be a dodgy gauge or a dodgy sender?

[Carbon 34]

crazy readings are coming from the ohm load , resistance changing, most likely a bad connection or solder joint , if the gauge powers up fine then check the sendor/sensor wire like I explained. is your gauge a stepper motor driven gauge ? some of those are so the voltage or ohm load would be more precises at each step , or temp

no idea what happened and this is typing on the wrong side now.. grrrrr